Security forces on Wednesday claimed to have arrested terrorists of the outlawed Taliban in different raids across the Punjab province days after a suicide bomber killed at least 26, most of them policemen, in Lahore.

Inter-Services Public Relations in a statement said security forces, including Punjab Rangers, the Counter-Terrorism Department and police, conducted operations in Lahore in a span of 24 hours.

The raids led to the arrest of at least 21 suspects, including members of the Taliban, Afghans living without documents and a criminal gang, the statement added.

The powerful blast Monday hit a busy vegetable market on a bustling main road in the southern part of Lahore, blowing out the windows in nearby buildings.

Many of those killed in the attack were police who were clearing shopping stalls that had illegally encroached on to the road.

On Tuesday distraught relatives carried the coffins of two policemen, brothers who were killed in the attack, to a petrol pump which had been turned into a makeshift prayer ground.

Floral wreaths from local police chiefs were placed on the wooden coffins as family members wept.

Police have said their initial investigations show the attack, claimed by the Pakistani Taliban, was carried out by a suicide bomber.

Lahore has been hit by significant militant attacks in Pakistan's more than decade-long war on extremism, but they have been less frequent in recent years.

The last major blast in the city was in March last year, when 75 were killed and hundreds injured in a bomb targeting Christians celebrating Easter Sunday in a park.

But the country was also hit by a wave of attacks in February this year, including a bomb that killed 14 people in Lahore.

In April a further seven were killed in an attack in the city targeting a team that was carrying out the country's long overdue census.

After years of spiralling insecurity, the powerful Army launched a crackdown on militancy in the wake of a brutal attack on a school in late 2014.

More than 150 people, most of them children, died in the Taliban-led assault in the northwestern city of Peshawar - the country's deadliest ever single attack.

It shook a country already grimly accustomed to atrocities and prompted the military to step up operations in the tribal areas, where militants had previously operated with impunity.

The country has seen a dramatic improvement in security since, though groups such as the Pakistani Taliban retain the ability to carry out massive attacks.